Chlorinated polyvinyl chloride is produced by chlorination of polyvinyl chloride and has a higher heat resistant temperature than the polyvinyl chloride. Therefore, the chlorinated polyvinyl chloride is used in various fields such as heat-resistant pipes, heat-resistant industrial boards, heat-resistant films, and heat-resistant sheets.
The synthesis of the chlorinated polyvinyl chloride may be performed by the following methods: one method includes suspending a polyvinyl chloride powder in an aqueous medium to form an aqueous suspension and chlorinating polyvinyl chloride while supplying chlorine to the aqueous suspension, and another method includes bringing a polyvinyl chloride powder and chlorine into contact with each other to react (e.g., Patent Documents 1 to 4).    Patent Document 1: JP 2002-275213 A    Patent Document 2: JP 2002-308930 A    Patent Document 3: JP 2002-317010 A    Patent Document 4: JP 2002-317011 A
To achieve large-scale production of chlorinated polyvinyl chloride by the method that includes bringing a polyvinyl chloride powder and chlorine into contact with each other to react, the productivity should be improved.